The proposed study is a pilot assessment of the agricultural pesticide exposure experience of older farm men and women. The major purpose of this study is to gain a better understanding of the health risks which may be related to pesticide exposure in older farm populations. The specific aims are to assess the present and historical pesticide exposure experience of older farm men and women. Two physiological responses to pesticides which may vary with age are identified for inclusion in the study; 1) cholinesterase inhibition from organophosphate exposure and 2) the response of the immune system to exposure to organophosphate insecticides and herbicides. The study will be conducted in two phases. Phase 1 will be conducted in Iowa and will collect detailed exposure histories from a small number of farm men and women, aged 55-75. Phase 1 will use exposure history and health questionnaire data collection instruments, industrial hygiene monitoring of actual pesticide exposure tasks, and biological monitoring of blood samples to screen for physiological effects. Phase 2 of the study will be to apply the refined questionnaire and industrial hygiene methods to a population of older black and white farmers in Arkansas. The long-term plans include using the pilot study to aid in designing a larger sample study of the toxicology in older farmers and a trial of an educational program targeted to reduce pesticide exposures in older farm populations.